The transmission electron microscope (hereinafter referred to as TEM) is helpful in observation of a microstructure of an observation subject irradiated with an electron beam accelerated at a high voltage (several tens to several hundreds of kV) and allowing the electron beam transmitting through the subject to form and magnify the image by means of the electromagnetic lens. Various types of examinations and developments of the microscope have been conducted. Especially, so-called phase contrast is one of elements which constitute an image contrast of the TEM. It is obtained by using a phase difference between a scattered wave and a non-scattered wave, which is caused by aberration and defocusing of the objective lens. As for the phase contrast, various phase plates have been proposed in order to realize the high contrast observation by applying the optical path difference (see Patent literatures 1 to 4, and Non-patent literature 1).
The patent literature 1 proposes the phase plate that changes the phase of the scattered wave using the inner potential of the amorphous thin film. The patent literatures 2 and 3 propose the phase plate for controlling the phase of the non-scattered wave using an electrostatic potential generated in space by the electrode to which the voltage is applied. The patent literature 4 proposes the phase plate by applying AB (Aharonov-Bohm) effect derived from the magnetic flux confined in the magnetic body.